Software, which controls a mobile communication terminal, performs various controls by making a timer circuit which is generally configured by hardware operate. The measurement employing a timer circuit is used in a case of arbitrating the timing in the hardware control and software processing, and in a case of monitoring the communication with an upper device being the other communication party.
In the former case, the measurement time period is generally short, and it is rarely necessary to measure a plurality of different sets of time concurrently using a timer circuit. On the other hand, in the latter case, a plurality of different sets of time are often measured with a plurality of different timings, and it is necessary to measure a plurality of different sets of time concurrently using a timer circuit. In case of measuring a plurality of different sets of time concurrently, the measurement can be realized by mounting all the required timer circuits. However, in this case, the circuit size becomes large, and, especially, this configuration is not practical for a mobile communication terminal which has to be reduced in size. Accordingly, by mounting limited required timer circuits, the minimum time period (for example, one second) is measured by the timer circuits, a CPU is periodically made to generate an interruption every measured minimum time period, counting is performed in the software processing by the CPU every time the interruption is generated, and the count value is updated. In this way, a plurality of time measurements with different sets of measurement time can be realized by starting the time measurements asynchronously.